The Hybridoma Core will be used by 29 UM-RDCC investigators who are pursuing research projects that require monoclonal antibodies. The primary purpose of the Hybridoma Core is to generate somatic-cell hybrids (hybridomas) that produce monoclonal antibodies of desired specificity. It is currently supported by the Michigan Diabetes Center, and by the RDCC for use by investigators within these centers. Services provided include immunization of mice, fusion of B lymphocytes with myeloma cells to create hybridomas, subcloning and cryopreservation of hybridomas, antibody isotyping, production of ascites in mice, and production of antibodies in vitro. Consultation is provided by the Core directors in strategies for immunization, and screening assays to ensure efficient generation and detection of the desired antibodies. The majority of hybridomas produced in the core are of murine origin, but rat, hamster and human hybridomas have also been produced. Since its establishment in 1980 the Hybridoma Facility has produced monoclonal antibodies against a wide variety of lymphocyte surface antigens, tumor cell antigens, purified proteins, cytokines, hormones, hormone receptors and recombinant proteins. Over the past thirteen years of UM-MAC/RDCC support (1988-2004) over 250 fusions were performed for investigators in these Centers. Subcloning was performed for more than 1250 hybridomas, and more than 1200 monoclonal antibody batches were produced in murine ascites. A variety of specialized procedures have been added to address various needs of UM-RDCC investigators including bulk production of monoclonal antibodies in vitro. The current proposal will allow this facility to continue to provide up-to-date hybridoma technology for UM-RDCC laboratories. The core will also provide collaborative and consultative services for the UM-RDCC investigators who may wish to select recombinant antibody-like, reagents from phage display libraries. Through these initiatives, the Hybridoma Core will remain on the cutting edge of monoclonal antibody technology, and continue to provide optimal service to a broad range of users who will contribute to the public health by using monoclonal antibodies for studying the pathogenesis, diagnosis and treatment of rheumatic diseases.